Display systems, such as digital signs, typically include an illumination device, such as a projector or backlit panel, and a display screen. During operation of the display system, the illumination device typically projects an image onto or through the display screen for presentation to viewers. The display screen can be a sheet-like optical device with a relatively thin viewing layer that is placed at an image surface of the illumination device.
Switchable display screens include polymer-dispersed liquid crystals that allow the illumination device to be transmitted or scattered in various sections by making the display screens or sections of the display screens transparent or diffuse depending upon the orientation states of the liquid crystals. The use of layered polymer-dispersed liquid crystals in display screens can increase the complexity of shapes that can be displayed, increase the number of haze levels, and allows the user to create patterns with fully clear and hazy sections simultaneously by stacking or layering patterned PDLC layers on top of one another.
Display systems can be used for advertising in malls, showrooms, exhibitions, and stores. Rear projection systems are one such example. A rear projection system includes at least a projection device (e.g. a three-color liquid crystal display projector that combines polarized light from different liquid crystal displays and emits combined light to form images) and a display screen. The projector can be configured to project an image within a limited projection area which may be a basic shape, such as a square or rectangle or other shape.